How to cut & replace PVC drain pipe

Written by steve sloane| 13/05/2017

Scrape away burrs from the pipe end using a utility knife. (Utility knife image by Andris Daugovich from Fotolia.com)

PVC drain pipe (also known as sewer pipe) is one of the two types of sewer pipe installed in modern-day homes (ABS black plastic pipe being the other). PVC pipes come in various diameters (1 1/2 to 4 inches) to serve different water fixtures, and are attached together with different angled PVC couplings, PVC primer and PVC cement. Once the cement has dried (in a matter of seconds), the PVC joint is very strong and resilient, and can only then be removed by cutting it from the pipeline.

Mark the existing PVC pipeline at the point where it needs to be cut and the new pipe installed. Cut through the PVC pipe at the mark, using either a hacksaw or handsaw. If possible, use a power saw to make a cleaner cut. Make sure that the cut is straight, and scrape away plastic fragments or burrs with a utility knife.

Cut the unwanted section of PVC sewer pipe into easily removable pieces, and take it away.

Apply PVC primer around the outside of the existing PVC pipe cut, as well as the inside of a PVC coupling. Wait 20 seconds for the primer to dry. Apply PVC cement to the primed pipe end and to one inside end of the coupling. Push the coupling onto the end of the pipe, and hold in place for 20 seconds while the cement dries.

Measure and cut a new piece of PVC pipe to the required length. Remove burrs and plastic fragments. Prime one end of the newly-cut pipe, and wait 20 seconds for it to dry. Apply cement to the primed end of the pipe, and the remaining inside end of the coupling. Push the pipe into the end of the coupling, and hold in place for 20 seconds. Now measure, cut and install new pipe and couplings until the water fixture is reached.

Tip

Sinks, showers, tubs and washing machines require P-traps to connect the sewer pipe to the fixture, whereas toilets require closet flanges and 90-degree elbow joints. PVC couplings are available in 30, 45, 60, 90 and 180-degree angles. Tee couplings are also used to connect one pipeline to another.